Roasted Root Vegetable Irish Lamb Stew

Name: Roasted Root Vegetable Irish Lamb Stew
Ingredients: 4 tablespoons olive oil; 3 pounds lamb shoulder, cut into 1 1/2 inch pieces; Salt; Freshly ground black pepper; 2 cups leeks, sliced; 1/2 cup flour; 4 ounces unsalted butter; 1 cup Guinness beer; 3 cups beef stock; 1 cup tomatoes, peeled, seeded and diced; 1/2 pound parsnips, peeled and cut into 2-inch pieces; 1/2 pound carrots, peeled and cut into 2-inch pieces; 1 pound russet potatoes, peeled and cut into 2-inch pieces; 4 cloves garlic, cut in half; 3 sprigs of fresh rosemary, plus 1 tablespoon chopped; 1 cup peas, shelled; 1 cup leeks, sliced thinly; Oil for frying